(1) Field of the Invention
The invention relates to a track leveling and ballast tamping machine comprising a standard vehicle capable of being coupled to a train and having a machine frame, two undercarriages supporting the frame for movement in an operating direction along a track comprised of two rails fastened to ties defining cribs therebetween, the undercarriages being sufficiently spaced apart in this direction to permit lifting of the track therebetween, and a drive for moving the frame along the track. A ballast tamping unit is connected to the frame between the undercarriages and comprises pairs of vibratory and reciprocatory tamping tools for tamping ballast under respective ones of the ties, a track lifting unit is connected to the frame between the undercarriages and ahead of the ballast tamping unit in the operating direction at a fixed distance therefrom, and a track leveling reference system controls the lifting of the track by the track lifting unit.
(2) Description of the Prior Art
Canadian Pat. No. 1,191,739, issued Aug. 13, 1985, discloses a track leveling, lining and tamping machine which intermittently advances from tamping stage to tamping stage. Such a machine may be used in conjunction with other track working machines, such as a ballast cleaning machine operating ahead of the track leveling, lining and tamping machine, in the operating direction, and a track bed stabilizing machine following the track leveling, lining and tamping machine to form a mechanical track rehabilitation train. The track working machines of this train are independently driven. The encrusted ballast removed from the track bed by the excavating chain of the ballast cleaning machine is cleaned thereon and the cleaned ballast is redistributed to enable the succeeding track leveling, lining and tamping machine to tamp the cleaned ballast under the leveled and lined track at the intersections of the ties and track rails. After stabilization, the lined track is firmly positioned at a correct level. However, the tamped ballast supports for the track at the intersections of the ties and rails are not always uniform because the cleaned ballast is not quite uniformly distributed by the ballast cleaning machine preceding the track tamper.
British Pat. No. 2,135,369, published Feb. 12, 1986, discloses a continuously moving track leveling, lining and tamping machine of this general type, which has a main frame advancing continuously along the track while a tool carrier between the undercarriages has one end pivotally connected to the main frame and an opposite end supported by a guide carriage for intermittently advancing the carrier from tamping stage to tamping stage. A tamping tool unit is mounted on the tool carrier immediately preceding the guide carriage, in the operating direction, and a track lifting and lining unit is arranged on the tool carrier preceding the tamping tool unit. An hydraulically operated cylinder-piston drive adjusts the position of the tool carrier relative to the main frame at the point where the one tool carrier end is pivotally supported on the main frame. Such a non-stop operable track tamper has not only proven to be very productive in track rehabilitation work but provides a much more comfortable working environment for the machine operators than conventional tampers, is highly energy-effective and greatly saves wear on the machine drive and brakes because the operators sitting on the heavy main frame are not subjected to intermittent acceleration and deceleration impacts.
U.S. Pat. No. 4,538,687, dated Sept. 3, 1985, discloses a non-stop operating ballast cleaning machine preceded, in the operating direction, by a track lifting and ballast tamping unit. This unit is longitudinally displaceable for intermittent advancement thereof and is pivotally coupled to the frame of the ballast cleaning machine. The track lifting and tamping unit enables the track to be lifted by tamping ballast under the ties so that the excavating chain of the succeeding ballast cleaning machine, which extends transversely in the ballast bed underneath the track, does not unduly bend the track rails.
Austrian Pat. No. 197,302, of Oct. 15, 1957, discloses a standard vehicle capable of being coupled to a train and having a frame supported on two undercarriages and carrying a ballast excavating chain, means for redistributing the cleaned ballast and a surface tamper for sufficiently compacting the redistributed ballast in the cribs to enable the rear undercarriage to travel on the track.
U.S. Pat. No. 4,479,439, dated Oct. 30, 1984, discloses a non-stop operating track rehabilitation apparatus comprising a work car with a ballast excavating chain, conveyor arrangements for the separate conveyance of sand and ballast, and a track lifting and tamping unit following the excavating chain, in the operating direction, may be longitudinally displaceably mounted on the work car. A freight train with a track for gantry cranes follows the work car. The sand and ballast required for the track rehabilitation are stored in containers on the freight train and are brought by gantry crane to a sand storage receptacle on the work car and a ballast storage receptacle on the train, respectively. In one embodiment, a track lifting and tamping unit is longitudinally adjustably mounted on a first freight car immediately following the work car and rearwardly of the ballast storage container mounted thereon. An input end of a ballast conveyor is positioned below the ballast storage container and a discharge end of the conveyor is positioned to throw the ballast on the excavated track bed behind the excavating chain. This track rehabilitation apparatus requires an exceptionally efficient conveyor arrangement for the sand and ballast because the sand layer and the ballast layer for the entire track bed are deposited in a single operating stage.
In connection with a track renewal train equipped for continuous replacement of track rails and ties, as disclosed, for example, in U.S. Pat. No. 4,160,418, dated July 10, 1979, a mobile flatbed car according to U.S. Pat. No. 3,680,486, dated Aug. 1, 1972, may be used, which has a series of operator's cabs mounted underneath the flatbed and conveyors for rail fastening elements conveying the fastening elements from and to the cabs to enable operators therein quickly to remove and attach the fastening elements for respectively detaching and attaching the rails from and to the ties. However, it may be difficult to fasten the laid rails to the ties with this apparatus because the deposition of ballast in the cribs may make it impossible for the fastening tools to engage the fastening elements.
U.S. Pat. No. 3,877,160, dated Apr. 15, 1975, and Austrian Pat. No. 353,820, dated Dec. 10, 1979, disclose ballast plow arrangements designed to distribute ballast uniformly over a track bed and to impart a desired profile to the ballast bed. A broom follows the ballast plow arrangement, in the operating direction, and sweeps excess ballast to an elevating conveyor preceding the broom and conveying the excess ballast into a ballast storage container.
Railway Gazette International, February 1985, pages 120/1, describes a track bed rehabilitation train in which a track rehabilitation machine is placed between a waste materials train ahead and a new material skip train behind. The old ballast is excavated and removed while a sand and superposed new ballast layer is deposited during the continuous advance of the train. The train comprises the centrally positioned track rehabilitation machine comprising a ballast excavating chain and conveyor arrangements for conveying the sand and new ballast to the machine, a satellite car and a number of freight cars following the machine. The satellite car runs on undercarriages at each end of the car and carries therebetween a track lifting and lining unit as well as a ballast tamping unit, the units being cyclically displaceable from tamping stage to tamping stage while the entire train advances continuously. While the old ballast excavated by the excavating chain is conveyed to silo cars ahead of the machine, containers filled with sand and new ballast are brought by gantry cranes to sand and ballast storage containers, respectively, whence the sand and new ballast is conveyed forwardly to a discharge point at the machine just behind the excavating chain. In addition to this primary ballast discharge point, another discharge of ballast is provided ahead of the tamping unit. The satellite car is integrated in the train by the track for the gantry crane and the conveyor arrangement for bringing the new ballast to the machine. While this installation has been used with great success, it requires highly efficient conveyor arrangements for the sand and the ballast.
U.S. Pat. No. 4,257,331, dated Mar. 24, 1981, discloses a mobile track surfacing machine comprising a ballast cleaning machine and a trailing track compacting machine coupled thereto. A thrust ballast tamping unit is longitudinally displaceably mounted on the frame of the trailing machine between the undercarriages thereof and a track lifting and lining unit precedes the thrust ballast tamping unit and is fixedly mounted on the frame. The tamping unit has thrust tamping tools immersible in the cribs for compacting the ballast therein, and this requires a relatively large amount of ballast, which is made available by extending a ballast conveyor beyond the rear end of the preceding ballast cleaning machine over a ballast storage bin at the front end of the trailing machine frame. The bin has a ballast output chute with a shutter controllable by a drive whereby clean ballast may be delivered in metered amounts into the cribs so that a sufficient amount of ballast is available for effective tamping by the thrust tamping tools, the major amount of the cleaned ballast being redistributed through the chute on the ballast cleaning machine. The ballast compaction provided by the thrust tamping tools in the cribs is useful only to provide sufficient track stability immediately after the ballast cleaning operation to permit high-speed train traffic to pass but this machine cannot be used for permanent and accurate track correction and tamping obtained with pairs of vibratory and reciprocatory tools tamping the ballast under the ties after the track has been properly positioned by a track lifting and lining unit keeping a constant distance from the tamping unit, the track lifting unit of the trailing auxiliary machine being fixed on the machine frame too close to the front axle to permit substantial track lifting while the crib ballast compacting unit moves back and forth.
Finally, European Pat. No. 0 057 128, published Aug. 4, 1982, shows a machine for the spot replacement of individual damaged railroad ties, which comprises a standard vehicle capable of being coupled to a train and having a frame, two undercarriages supporting the frame and spaced apart in an operating direction, and a drive for moving the frame along the track. A ballast tamping unit is mounted on the frame between the undercarriages and comprises pairs of reciprocatory tamping tools for tamping ballast under the ties. A ballast receiving and storage container is centrally mounted on the frame immediately ahead of the tamping unit and has adjustable outlet port means for distributing ballast in the cribs. A ballast conveyor is arranged on the frame for conveying ballast to the ballast receiving and storage container in the center of the frame from a rear end thereof, in the operating direction. A tie conveying and gripping apparatus is mounted on the frame between the undercarriages immediately ahead of the container. This type of machine is used for the replacement of individual damaged ties by new ties. Since the new tie lies loosely on the track bed, ballast is distributed through the outlet port means at the newly laid tie, and this ballast is then spot tamped under the tie. The machine has a device for holding the track at its level while the spot tamping proceeds. Only individual ties, or at most two ties at a time, may be replaced with this machine in any operating cycle. Such a machine can be used in practical operations only as an auxiliary machine for the replacement of one or two ties at a time and if it were used along a track section which has many damaged ties that need replacement, this track section would become worse and worse as the machine advances thereover. A cyclic tamping of successive ties in a continuous operation along an extended track section is neither possible nor contemplated with this machine which has no track correction reference system, and since the correction of one tie would destroy the position of the other, ties.